全文获取类型
收费全文 | 3447篇 |
免费 | 282篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 84篇 |
妇产科学 | 30篇 |
基础医学 | 398篇 |
口腔科学 | 85篇 |
临床医学 | 476篇 |
内科学 | 639篇 |
皮肤病学 | 46篇 |
神经病学 | 281篇 |
特种医学 | 229篇 |
外科学 | 420篇 |
综合类 | 115篇 |
一般理论 | 2篇 |
预防医学 | 316篇 |
眼科学 | 59篇 |
药学 | 245篇 |
1篇 | |
中国医学 | 2篇 |
肿瘤学 | 294篇 |
出版年
2022年 | 28篇 |
2021年 | 54篇 |
2020年 | 33篇 |
2019年 | 50篇 |
2018年 | 75篇 |
2017年 | 56篇 |
2016年 | 58篇 |
2015年 | 65篇 |
2014年 | 107篇 |
2013年 | 158篇 |
2012年 | 194篇 |
2011年 | 222篇 |
2010年 | 129篇 |
2009年 | 124篇 |
2008年 | 195篇 |
2007年 | 210篇 |
2006年 | 210篇 |
2005年 | 204篇 |
2004年 | 168篇 |
2003年 | 194篇 |
2002年 | 187篇 |
2001年 | 48篇 |
2000年 | 23篇 |
1999年 | 30篇 |
1998年 | 70篇 |
1997年 | 73篇 |
1996年 | 70篇 |
1995年 | 51篇 |
1994年 | 48篇 |
1993年 | 52篇 |
1992年 | 33篇 |
1991年 | 38篇 |
1990年 | 30篇 |
1989年 | 24篇 |
1988年 | 33篇 |
1987年 | 24篇 |
1986年 | 15篇 |
1985年 | 22篇 |
1984年 | 20篇 |
1983年 | 22篇 |
1982年 | 27篇 |
1981年 | 26篇 |
1980年 | 19篇 |
1979年 | 18篇 |
1978年 | 27篇 |
1977年 | 22篇 |
1976年 | 26篇 |
1975年 | 19篇 |
1974年 | 17篇 |
1971年 | 16篇 |
排序方式: 共有3746条查询结果,搜索用时 15 毫秒
1.
Ming Zhao Cheng Simon C F Rawlinson Andrew A Pitsillides Gul Zaman Subburaman Mohan David J Baylink Lance E Lanyon 《Journal of bone and mineral research》2002,17(4):593-602
The mechanism by which mechanical strain and estrogen stimulate bone cell proliferation was investigated using monolayer cultures of human osteoblastic TE85 cells and female human primary (first-passage) osteoblasts (fHOBs). Both cell types showed small but statistically significant dose-dependent increases in [3H]thymidine incorporation in response to 17beta-estradiol and to a single 10-minute period of uniaxial cyclic strain (1 Hz). In both cell types, the peak response to 17beta-estradiol occurred at 10(-8) - 10(-7) M and the peak response to strain occurred at 3500 microstrain ((mu)epsilon). Both strain-related and 17beta-estradiol-related increases in [3H]thymidine incorporation were abolished by the estrogen receptor (ER) modulator ICI 182,780 (10-8 M). Tamoxifen (10(-9) - 10(-8) M) increased [3H]thymidine incorporation in both cell types but had no effect on their response to strain. In TE85 cells, tamoxifen reduced the increase in [3H]thymidine incorporation associated with 17beta-estradiol to that of tamoxifen alone but had no such effect in fHOBs. In TE85 cells, strain increased medium concentrations of insulin-like growth factor (IGF) II but not IGF-I, whereas 17beta-estradiol increased medium concentrations of IGF-I but not IGF-II. Neutralizing monoclonal antibody (MNAb) to IGF-I (3 microg/ml) blocked the effects of 17beta-estradiol and exogenous truncated IGF-I (tIGF-I; 50 ng/ml) but not those of strain or tIGF-II (50 ng/ml). Neutralizing antibody to IGF-II (3 microg/ml) blocked the effects of strain and tIGF-II but not those of 17beta-estradiol or tIGF-I. MAb aIR-3 (100 ng/ml) to the IGF-I receptor blocked the effects on [3H]thymidine incorporation of strain, tIGF-II, 17beta-estradiol, and tIGF-I. HOBs and TE85 cells, act similarly to rat primary osteoblasts and ROS 17/2.8 cells in their dose-related proliferative responses to strain and 17beta-estradiol, both of which can be blocked by the ER modulator ICI 182,780. In TE85 cells (as in rat primaries and ROS 17/2.8 cells), the response to 17beta-estradiol is mediated by IGF-I, and the response to strain is mediated by IGF-II. Human cells differ from rat cells in that tamoxifen does not block their response to strain and reduces the response to 17beta-estradiol in TE85s but not primaries. In both human cell types (unlike rat cells) the effects of strain and IGF-II as well as estradiol and IGF-I can be blocked at the IGF-I receptor. 相似文献
2.
3.
4.
Stefano Sdringola Catalin Loghin Fernando Boccalandro K Lance Gould 《Journal of nuclear medicine》2006,47(1):59-67
Changes in regional myocardial perfusion throughout the entire coronary vascular tree, as opposed to changes in the worst regional perfusion defect, have not been described during long-term regression or progression of coronary artery disease (CAD) or related to clinical outcomes. METHODS: Four-hundred nine patients with CAD undergoing dipyridamole PET at baseline and after 2.6 +/- 1.4 y were followed over 5 more years for coronary events. PET images were objectively quantified by automated software for changes in severity of the (i) baseline worst quadrant, indicating the worst flow-limiting stenosis at baseline PET; (ii) follow-up worst quadrant, indicating the worst stenosis on follow-up PET; and (iii) maximal change quadrant, indicating the largest change of any same quadrant pair from baseline-to-follow-up images. RESULTS: At follow-up PET, new regional perfusion defects were seen in 40% of patients. In 77% of patients, the greatest change was in a quadrant different from the worst baseline defect. The maximal change quadrant improved in 70% of patients on intense lifestyle and pharmacologic lipid treatment, in 48% on moderate treatment, and in 39% on poor treatment (P < 0.0001). Combined quadrant changes integrated throughout the heart independently predicted cardiovascular events at long-term follow-up. In contrast, changes of any single baseline-to-follow-up quadrant pair did not. CONCLUSION: By PET, 77% of patients with CAD had the greatest perfusion changes in areas different from the baseline worst perfusion defect and 40% had new perfusion defects. Changes in perfusion defects throughout the entire coronary vascular tree predicted coronary events, whereas changes in the worst flow-limiting stenosis at baseline or in any one segment of myocardium did not. To our knowledge, these data provide the first direct evidence on mechanisms for disproportionately greater reduction in cardiac events than changes in single stenosis severity with lipid treatment. 相似文献
5.
De Leo V; Morgante G; Lanzetta D; D'Antona D; Bertieri RS 《Human reproduction (Oxford, England)》1997,12(2):357-360
We report the results of administration of danazol after suspension of
gonadotrophin-releasing hormone analogue (GnRHa) therapy for uterine
myomas. A total of 21 women with uterine myomas was treated with 100 mg
danazol for 6 months after GnRHa therapy. Uterine volume and endocrine
status were monitored monthly by ultrasound and assay of plasma
gonadotrophins, oestradiol and progesterone. The results show a rebound of
uterine volume about 30% less than in controls at the end of danazol
therapy. Menstrual cyclicity returned after 65 +/- 3 days in 16 subjects
and five patients remained amenorrhoeic. Hormone assays confirmed renewed
ovarian function in the women whose menstrual periods returned. Bone
mineral content was substantially reduced during GnRHa treatment but
improved significantly during danazol therapy even in the women who
remained amenorrhoeic. These results show the utility of danazol in
prolonging the therapeutic effects of GnRHa. The mechanism by which danazol
inhibits rebound of uterine volume may be due to its antiprogesterone
effects on uterine myomas.
相似文献
6.
7.
8.
9.
Frances Chung Doris Tong Paula C. Miceli Joseph Reiz Zoltan Harsanyi Andrew C. Darke Lance W. Payne 《Journal canadien d'anesthésie》2004,51(3):216-221
PURPOSE: Following ambulatory surgery, long-acting analgesics may provide advantages over short-acting analgesics. This study compared controlled-release codeine (CC) and acetaminophen plus codeine (A/C; 300 mg/30 mg) for pain control in the 48-hr period following laparoscopic cholecystectomy. METHODS: Eligible patients were randomized to CC or A/C in a double-blind, double-dummy parallel group study. Unrelieved pain in hospital was treated with fentanyl i.v. bolus. Pain [100 mm visual analogue scale (VAS)] was assessed before the first dose of medication; at 0.5, one, two, three, and four hours post-dose; at discharge; and three times a day for 48 hr. Adverse events were recorded and measures of patient satisfaction were assessed at the end of the study. RESULTS: Eighty-four patients were enrolled in the study; 42 patients in each group. There were no statistically significant differences between CC and A/C treatment. Mean VAS baseline pain was similar in both groups (P = 0.49) and there was no significant difference in the time to onset of analgesia (P = 0.17). At 0.5 hr, the mean VAS pain score was significantly reduced from baseline in both groups (P = 0.0001). The VAS pain scores at discharge were reduced 59% and 56% from baseline, respectively (P = 0.61). There was no difference between treatments in the incidence of adverse events and patients reported similar levels of satisfaction. CONCLUSIONS: Controlled-release codeine provides an equivalent onset of analgesia, reduction in postoperative pain, and level of patient satisfaction, to acetaminophen plus codeine, over 48 hr following cholecystectomy, with the advantage of less frequent dosing. 相似文献
10.